Internal combustion engines conventionally require the mixing of an oxidizing material with fuel prior to entry of the fuel into a combustion chamber, the efficiency of this mixing being one of the most important factors in the overall efficiency of the engine. Typically, charge-forming devices are used in association with an internal combustion engine to mix fuel and oxidizer, usually air, to form a combustible charge which is then directed into the combustion chamber for burning. While certain engines operate somewhat differently, this same method of operation applies generally to all power plants which produce power by combustion of a fuel. In the most commonly used of these power plants, the charge-forming device is a "carburetor," a term loosely applied to literally thousands of widely differing yet generally similar devices which mix air/fuel to form a combustible charge prior to entry of the charge into the engine itself. Although many years of intensive effort have been directed toward production of efficient carburetion devices, it remains the case that this step of mixing fuel and air is a substantial cause of incomplete combustion within the engine. Incomplete combustion of fuel results in a lowered realization of the energy present in the fuel or, as is commonly said, results in "wasting gas."
Typically, carburetors have moving parts which must function in a cyclic manner to cause proper proportions of air and fuel to mix. Essentially all of the fuel introduced into the conventional carburetor is made a part of a given fuel/air charge and is drawn into the engine for combustion. Accordingly, the fuel introduced into the carburetor is thereby introduced into the engine even though the quantity of fuel may be excessive for efficient combustion. Due to the nature of prior charge-forming devices, as particularly embodied in the moving parts and in the functional interrelationship of these parts, inefficiencies in the utilization of fuel result. A continuing need thus exists in the art for apparatus capable of providing an efficient mixing of fuel and air to facilitate complete combustion in an engine.
The present invention is thus seen to provide apparatus for efficiently mixing fuel and air for delivery to an engine. The present apparatus functions to vaporize at least a portion of fuel introduced thereinto and to intimately mix this vaporized fuel with air prior to introduction of the resulting fuel/air mixture into the engine for combustion. The improved fuel/air mixing produced by the present apparatus allows more efficient combustion of the fuel by the engine, thereby resulting in greater utilization of the energy potential of the fuel and thus effecting economies by producing a greater amount of useful work for a given quantity of fuel. Operation of an engine used with the present apparatus is demonstrably more economical than the same engine operated with prior carburetion or other fuel supplying devices.
The present apparatus in its essence does not require moving parts and basically comprises a chamber within which air and fuel are caused to mix. The chamber is provided with an internal and inverted U-shaped shroud which separates the chamber into spatial volumes which communicate only along lower edges of the shroud. Fuel is introduced into the chamber above the shroud and impinges on outer surfaces thereof, at least a portion of the fuel flowing downwardly along the outer surfaces of the shroud in a relatively thin film. The fuel thus reaches the lower portion of the chamber and mixes with air entering the chamber from inlets disposed along lower side portions of a housing defining the chamber. The incipiently mixing air and fuel then move under the lower edges of the shroud into that volume lying within the interior confines of the shroud. An apertured air feed tube extends along the shroud internally of the volume confined by the shroud, the feed tube communicating with ambient at one end to draw air into the tube under the influence of a vacuum such as is created by the engine and as is connected to the other end of the feed tube. Turbulence within the chamber and within the feed tube is created by air moving within the feed tube, at least a portion of the air entering the chamber through the apertures in the feed tube to further mix with the air and fuel moving into the space under the shroud. Fuel and air thus become more intimately mixed under the shroud with the fuel becoming more completely vaporized. A continuous stream of mixed fuel and air is then drawn through the apertures into the feed tube and is directed into the engine, such as through the intake manifold, for combustion. Fuel not vaporized pools in a a return sump located at the bottom of the chamber, the unvaporized fuel being returned to the fuel tank or otherwise held for reintroduction into the chamber. Accordingly, fuel not sufficiently vaporized for efficient combustion is not charged into the engine but is "recycled".
Given the foregoing general description of the structure and operation of the present apparatus, it follows that a primary object of the several embodiments of the invention is to provide apparatus for efficiently mixing fuel and air for introduction into an engine or other fuel burning apparatus to effect more nearly complete combustion of the fuel than is possible with conventional charge-forming devices such as carburetors and the like.
It is another object of the invention to provide a fuel and air mixing apparatus which can be readily adapted to use with conventional and internal combustion engines such as are used to power vehicles without the need for substantial modification of such engines.
It is a further object of the invention to provide an improved fuel and air mixing apparatus capable of efficiently vaporizing fuel and mixing only vaporized fuel with air for delivery to a combustion chamber of an engine or other fuel burning apparatus in order to facilitate more nearly complete combustion of the fuel, unvaporized fuel being recycled into the apparatus for subsequent vaporization and mixing.
Further objects and advantages of the invention will become more readily apparent in light of the following detailed description of the preferred embodiments.